Enhanced golf club performance via friction stir processing

Abstract

Friction stir processing (FSP) provides a hardened golf club face that more efficiently transfers momentum between the golf club and the ball, increasing the launch velocity so as to provide increased loft (for a given distance traveled by the ball). The FSP hardened face is also more resistant to wear so that the golf club provides more consistent performance and lasts longer. A practice club having a friction stir processed sweet spot on the face may enable the golfer to feel whether the ball has been hit by the sweet spot.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention is concerned with fabrication of golf clubs, and in particular with surface treatment of metallic golf club heads to improve performance. [0003] 2. Description of the Related Art [0004] Golf club irons are generally designed to propel a golf ball through a trajectory for which the increase in the ball height (i.e., loft) for a given distance traveled is maximized. In this case, the ball impacts the ground at a relatively large angle so that it tends to roll less and remain close to the point of ground impact, which enables the golfer to exercise better control over the final location of the ball. For a high-quality golf club, properly swung, the ball should go “straight”, i.e., its trajectory should define an arc lying in a vertical plane. This requires that horizontal spin be minimized so that the ball does not substantially hook to the left or slice to the right of the “straight” trajectory. On the ...

AI Technical Summary

Benefits of technology

[0010] This invention provides an improved golf club and a method for improving the performance of a golf club via friction stir processing (FSP) to enhance the hardness of at least a portion of the golf club face. Enhanced face hardness tends to increase the momentum transfer efficiency between the club and the ball so as to provide increased loft, increased distance, and better control over the final location of the ball. Friction stir processing also tends to remove voids and defects in the metal that might otherwise decrease momentum transfer efficiency. The friction stir processed face is also more resistant to wear, which tends to improve golfing consistency and extend the lifetime of the club. Another embodiment of the invention is a practice club that provides performance feedback to the golfer in terms of a more solid feel when the ball is struck within a friction stir processed sweet spot.

[0011] Friction stir processing, according to the present invention, may be performed after the golf club head is formed by casting or forging, for example, or may be performed on a workpiece subsequently formed into a club head, by forging, for example. The FSP depth is typically sufficiently small such that the forgability, mechanical properties, and impact resistance of the underlying bulk metal are substantially unaffected. This provides enhanced flexibility with respect to golf club fabrication and peripheral weighting, especially for forged clubs. It is generally necessary to re-surface the friction stir processed area, preferably by milling. As part of the re-surfacing operation, desirable features (grooves, for example) may be machined in the club face. The FSP treatment is inexpensive to apply, enabling high quality golf clubs to be fabricated at reduced costs.

Problems solved by technology

Friction stir processing also tends to remove voids and defects in the metal that might otherwise decrease momentum transfer efficiency.

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